JPH061396B2 - Image scaling device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image scaling device that identifies an image area recorded on a document and scales it according to the size of the recording paper.

[Prior art and its problems]

Conventionally, the automatic scaling ratio setting means in this type of image scaling device sets the copying paper size to be fed, and sets the copying magnification by comparing the original size detected by various methods with the copying paper size. Therefore, when the image area in the original size is extremely small, there is a drawback that the copied image has a margin and is very difficult to read.

The present invention has been made in order to eliminate the above-mentioned drawbacks, and identifies an image area recorded on a document, and also identifies an image state on the boundary between the image area and the document, and according to a designated recording paper size. Image scaling that allows you to perform image recording without excess or deficiency of the original image on the entire surface of the specified size of recording paper and without losing the image on the boundary between the original and the image. The purpose is to provide a device.

〔Example〕

FIG. 1 is a schematic sectional view showing an embodiment of an image scaling apparatus according to the present invention, FIG. 2 is a control circuit diagram of the same, and FIG. 3 is a front view of a reflection density detection element thereof.

In FIG. 1, 1 is a drum, 2 is a pre-electrification charger, 3 is a temporary charger, and 4 is a charger, and the corona is erased from the drum 1. 5 is a copying charger (transfer means), and 6 is a cleaning device, which is composed of a cleaning roller and an elastic blade. Reference numeral 7 is a developing device, and 8 is a pre-exposure lamp, which removes electricity from the drum 1. Reference numeral 9 denotes an entire surface exposure lamp, which forms an electrostatic latent image on the drum 1. Paper feed rollers 10 and 11 and an upper cassette 12 hold copy sheets. 13 is a lower cassette, 14 is a registration roller, 15 is a conveyor belt, 1
6 is a fixing roller, 17 is a discharge roller, 18 is a tray, 1
Reference numeral 9 is a document table glass (document table), 20 is a document, 21 is a document pressure plate, and the surface in contact with the document 20 is coated with a mirror surface or a member having a low reflectance. Reference numerals 22 and 23 are standard white plates, and 24 is a moving optical unit (scanning means), which comprises an irradiation lamp 25 and a first scanning mirror 26. 27 is a second scanning mirror, 28 is a position detecting piece, and the moving optical system unit 24
It is provided outside of. Reference numeral 29 is a switch for detecting a contact state between the original pressure plate 21 and the original table glass 19.

Position sensors 30, 31, 32 detect the position detecting piece 28. Reference numeral 34 denotes a document detection lens that forms an image of the reflected light guided to the first scanning mirror 26 and the second scanning mirror 27,
Reference numeral 35 denotes a reflection density detector in which a group of light receiving elements such as CCDs are arranged in a line in the main scanning direction B (direction perpendicular to the sub-scanning direction A), and the document size of the document 20 placed on the platen glass 19, The image area in the document, the reflection density of the document, and the position of the document in the copyable area are detected. Reference numeral 36 denotes a projection lens which forms an image of the reflected light guided to the second scanning mirror 27,
37 is a third scanning mirror, 38 is a fourth scanning mirror, 39 is an optical system drive motor, and drives the moving optical system unit 24. A main motor 40 drives the drum 1. 41
Is an eraser that prevents toner from adhering to the non-image area on the drum 1. The eraser 41 is a reflection density detector 35.
It is composed of an LED group which emits light corresponding to one pixel of the light receiving element group. Therefore, the erasers 41 are also arranged in a line in the main scanning direction B.

In the control circuit of FIG. 2, reference numeral 51 is an oscillator, which oscillates a clock signal. Reference numeral 52 is a frequency divider, 53 is an amplifier for amplifying the detection signal of the reflection density detector 35, 54 is an A / D converter, and the output of the amplifier 53 is A / D converted and the digital value is input to each of the input ports ₁ to _4. Output to. A microprocessor (MP) 55 receives each sensor output, the output of the reflection density detector 35, each timing signal at each input port,
Each control signal is output from each output port. This MP55
Is equipped with an internal timer and also constitutes the determining means of the present invention. 56 is _PAM, 57 1 to 57 ₃ being randomly accessed by the MP55 in cassette size input key constituting the specifying means of the present invention, and inputs the cassette size to each of the input ports _9-11 of MP55.

Reference numeral 58 is an input key such as a copy start key, a numeric keypad, a clear key or the like, which inputs a copy start signal, a copy number signal, a clear signal and the like to the respective input ports ₁₃ to ₁₆ of the MP55. 59 is a D / A converter, MP55 is a ramp signal to D / A conversion to the illumination lamp 25 which is output to the output ports _O 13 _{~ O 16.} Reference numeral 60 is an amplifier for amplifying the lamp signal, and 61 is a lamp regulator (CVR), which controls the voltage of the irradiation lamp 25. 62 is a drive driver,
The MP 55 receives the eraser drive control signal output to the output ports O _{1 to} O ₉ and drives the eraser 41. Reference numeral 63 is a drive driver, and the MP55 is provided for each output port O ₂₁ , O _22.
The optical system drive motor 39 is driven in response to the motor drive control signal output to. An AND circuit 64 ₁ takes the AND of the output signal of the frequency divider 52 and the control signal output from the MP 55 to the output port O ₁₂ , and inputs the shift pulse signal (SH) to the reflection density detector 35. 64 ₂ similarly output signal and MP55 of the frequency divider 52 is an AND circuit which takes the AND of the output control signal to the output port O _11, receives the clock signal phi ₁ to the reflection density detector 35. 65 ₁ inverter for inverting a signal from the oscillator 51, 65 ₂ AND circuit takes AND of the divider 52 and the inverter 65 _1, the input port ₅ of MP55 the A / Din signal
To enter. 66 inputs the clock signal phi ₂ of the AND circuit 64 _2. 67 is an input port of the MP55
₆ is a clock signal input to the input terminal ₆ . The output of the switch 29 is input to the input port ₁₂ of the MP55.

In the image scaling device configured as described above, when the document placed on the document table glass 19 (document table) is scanned by the moving optical system unit 24 (scanning unit), the reflected image is detected by the detecting unit (reflection unit). The pixel density information is detected by the density detector 35) and the pixel density information is stored in the RAM 56. This RAM56
When the discriminating unit (MP55) discriminates the pixel density information stored in the disc, discriminates the image region, and if it is determined that the image region and the size of the recording paper are different, the image in the image region is scaled. Forming means (projection lens 3,
(Drum 1 etc.) and the MP55 determines that the image area and the recording paper size match,
When it is determined that an image exists in the contour portion of the document area (steps of the flowchart shown in FIG. 8C described later)
In (28) to step (35)), since the forming means is controlled so that the image in the image area is reduced and a latent image is formed,
An image can be recorded on the entire surface of the recording paper of the designated size without excess or deficiency of the original image and without erasing the image on the boundary between the image and the original.

In the reflection density detector 35 of FIG. 3, reference numeral 71 denotes a light receiving element group composed of light receiving elements (1 to N), which divides the reflected light in the entire area in the main scanning direction of the originals arranged in one row into 1 to N. The light is received and the output voltage (V) corresponding to the reflection density (D) is output as shown in FIG.

Next, the original exposure and copying operations of the image scaling device will be described with reference to FIGS. 1 and 2.

The surface of the drum 1 is a photoconductor, and the main motor 4 is operated by turning on the copy start key of the input keys 58.
With 0, rotation starts in the direction of the arrow. By this rotation, the document 20 placed on the platen glass 19 (hereinafter, the light receiving surface of the platen glass 19 is referred to as a copyable area) is slit-exposed by the irradiation lamp 25 integrated in the optical system moving unit 24, The reflected light is scanned by the first scanning mirror 26 and the second scanning mirror 27. By moving the first scanning mirror 26 and the second scanning mirror 27 at a speed of 1: 1/2, the original 20 is scanned while the optical path length in front of the projection lens 36 is always kept constant, and the moving optical system is moved. The unit 24 is driven by the optical system drive motor 39. At this time, the reflected image that has passed through the projection lens 36, the third scanning mirror 37, and the fourth scanning mirror 38 is already the pre-exposure lamp 8
Then, a high-contrast electrostatic latent image is formed on the drum 1 which has been discharged by the pre-charger 2 at the same time and which has been corona-charged by the primary charger 3 via the charger 4. The electrostatic latent image formed on the drum 1 is developed by the developing roller of the next developing device 7 to be visualized as a toner image, and this toner image is copied onto copy paper. After copying, the drum 1 continues to rotate and is cleaned by the cleaning roller and the elastic blade of the cleaning device 6 to prepare for the next image formation.

The copy paper stored in the upper cassette 12 or the lower cassette 13 is conveyed into the machine by the paper feed rollers 10 and 11, and the registration rollers 14 temporarily stop the copy paper sent toward the drum 1 and set the leading edge of the copy paper. The copy paper is fed again in the direction of the drum 1 at the timing when the leading edges of the latent images coincide. Then, the toner on the drum 1 is copied onto the copy paper while the copy paper passes between the copy charger 5 and the drum 1. After the copying is completed, the copy paper is separated from the drum 1 and guided to the fixing roller 16 by the conveyor belt 15, and is pressed and heated to fix the copied image. Then, the discharge roller 1
The copy paper is discharged to the tray 18 by 7.

Next, the operation of detecting the document position, document size, and document density will be described with reference to the drawings.

After the main switch is turned on, first, the optical system drive motor 39 is driven to correct the characteristic variation of the light receiving element group 71 constituting the reflection density detector 35 and the ripple of the light source, and the position sensor 30 indicating the position of the standard white board 22 is moved. The moving optical system unit 24 is moved until the position detection piece 28 attached to the outside of the optical system unit 24 is detected. Next, when the irradiation lamp 25 irradiates the standard white plate 22 that provides a uniform reflection density, the reflected light is reflected by the first scanning mirror 2.
6, the second scanning mirror 27, and the document detection lens 34 are used to enter the reflection density detector 35. This reflection density is stored in the RAM 56 as a density correction value. After that, the optical system drive motor 39 is driven, and the moving optical system unit 24 is moved until the position sensor 31 indicating the tip of the copyable area detects the position detecting piece 28. Next, the original pressure plate 2
In the state where 1 is closed, the irradiation lamp 25 irradiates the copyable area on the platen glass 19 on which the document 20 is placed, and the measurement of the reflection density of the copyable area is started.

FIG. 5 is a view showing the correlation between the original 20 and the eraser 40. In FIG. 5 (I), the original 20 is the original table glass 19 and the original pressing plate 21.
And (II) shows a state in which the document 20 is placed on the platen glass 19, and (III)
Indicates the relationship between the eraser 41 and the drum 1. Fifth
In (II) of the figure, A indicates the sub scanning direction, B indicates the main scanning direction,
The shaded area indicates the image area. In addition,
Reference numerals 1 to n ', 1 to N, 1 to m', and 1 to 3 denote areas divided corresponding to the light receiving element group 71 of the reflection density detector 35.

Now, the reflection density detector 35 having the light receiving element group 71 finely divided in the main scanning direction B shown in FIG. 5 (II) detects the reflection density of the entire copyable area as the moving optical system unit 24 moves. Then, the value is corrected by the density correction value and stored in the RAM 56 as the image density. That is, the moving optical system unit 24 is moved in the sub-scanning direction A shown in FIG. 5 at a predetermined speed (for example, 260 mm / sec; at equal magnification), the illumination lamp 25 is irradiated again, and the original table glass 19 is irradiated.
Of the reflection density in the entire copyable area, the value is corrected by the density correction value, and the image density is stored in the RAM 56.
Remember. Therefore, by performing this operation, the reflection density obtained by finely dividing the entire copyable area into a mesh shape is detected as shown in FIG. From the image density obtained by correcting the reflection density with the density correction value, the document size, the image area in the document, and the maximum and minimum information of the reflection density of the document can be obtained. The MP 55 sends each control signal from these information.

When the standard white plate 23 is installed near the rear end of the image area as shown in FIG. 1, the position of the moving optical system unit 24 is confirmed by the position sensor 30, and then the standard white plate 23 is irradiated. After obtaining the density correction value by scanning, the moving optical system unit 24 is scanned in the sub-scanning direction A from the position of the position sensor 32 indicating the rear end position of the copyable area to the position of the position sensor 31, and the original copy is performed as described above. The reflection density is measured by dividing the entire possible area into a mesh.

Next, the operation of the control circuit of the embodiment of the present invention will be described with reference to the control circuit of FIG. 2 and the timing chart of the control signal of FIG.

First, after the main switch is turned on, in order to measure the reflection density of the standard white plate 22, the MP 55 outputs a motor control signal for driving the optical system drive motor 39 to the output port O ₂₁ ,.
After outputting to O ₂₂ , the moving optical system unit 24 is moved until the position sensor 30 detects the position detecting piece 28 as described above, and then the standard white plate 22 is irradiated by the irradiation lamp 25. Then, the shift pulse signal SH shown in FIG. 6 is applied to the reflection density detector 35, and the clock signal CLOCK oscillated by the oscillator 51 is further divided by the frequency divider 52 to obtain a clock signal φ ₁ and its inverted signal. Signal φ
Give ₂ to operate. The reflected light of the standard white plate 22 is detected by each element 1 to N of the light receiving element group 71, the output voltage is amplified by the amplifier 53, and this output signal OS is converted into a digital value by the A / D converter 54. However, as shown in FIG.
Process as (a) (hereinafter referred to as dummy process). Here, the dummy process is a process of removing an unnecessary signal (dummy signal) from the signals of one scanning line output from the reflection density detector 35. After that, A / shown in FIG.
The reflection density is read at the timing designated by the Din signal, and when the detection signal (b) is read from 1 to N times, the dummy signal (b) is counted for the predetermined dummy signal and the dummy process is performed again. The read reflection density data is stored in the designated area of the RAM 56 as a density correction value. Next, after the MP55 finishes the dummy process,
The irradiation lamp 25 is turned off and the input start of the copy start key of the input keys 58 is awaited.

Next, when the input of the copy start key is applied to the MP55, the MP55 turns on the optical system drive motor 39, starts the irradiation of the irradiation lamp 25, and moves the position sensor 31.
Until the position detecting piece 28 is detected by the moving optical system unit 2
After moving 4, the reading of the original image is started. While the moving optical system unit 24 moves in the sub-scanning direction A shown in FIG. 5, the MP55 starts an internal timer of the MP55 so as to output the shift pulse signal SH to the reflection density detector 35 at a predetermined interval (for example, 10 msec). A shift pulse signal SH is output every time the internal timer counts. Then, the MP 55 starts counting the A / Din signals in order to perform the dummy processing together with the output of the shift pulse signal SH, and at the time when a predetermined number of A / Din signals have been counted, it is considered that the dummy processing has ended, and thereafter, A / Din Each of the input ports _{1 of the} MP55 sequentially from the reflection density data 1 to N at the read timing designated by the Din signal
₄ to ₄ and performs correction with the density correction value stored in the RAM 56, and the image density data is stored in the RAM 56.
It is stored in the designated area of. And MP55 is 1 to N
After inputting the reflection density up to
The dummy process similar to the above is performed again until the counting of the in signal is completed, and when the dummy process is completed, the process waits until the counting of the internal timer is completed. Then, when the count of the internal timer is completed, the shift pulse signal SH is applied again to the reflection density detector 35, the internal timer is restarted, and the same processing as described above is repeated.

This operation is repeated up to the number M in the sub-scanning direction A, and the image density in the copyable area is obtained from the reflection density detected by the reflection density detector 35 as shown in FIG. The position and the document density are determined. The drive driver 62 is driven according to the document position, and signals for controlling the eraser 41 are output from the output ports O ₁ to O ₁ .
Output to O ₉ to prevent toner adhesion to the non-image area. Further, the original density stored in the RAM 56 is compared with predetermined reference black level values and reference white level values to obtain the maximum density and the minimum density, so that the optimum contrast is obtained, for example, the bias value of the developing device 7. To control.

Next, the control of the eraser 41 based on the reflection density detected by the reflection density detector 35 will be described with reference to FIGS. 1 and 2.

The eraser 41 is configured to emit light corresponding to each pixel of the light receiving element group 71 of the reflection density detector 35.
From the image density stored in M56, a set of pixels having a reflectance lower than a predetermined reflectance, that is, a non-original area is obtained. LE of the eraser 41 for this non-document area
D is caused to emit light according to the copy magnification to prevent toner from adhering to this non-original area.

Further, the reflectance of the pixels on the boundary between the non-original area and the original area is lower than that of the white original when the original pressure plate 21 is configured by a mirror surface or the like. Toner adheres to the contour of the. In order to prevent this, the LEDs of the eraser 41 corresponding to the pixels on the boundary between the non-original area and the original area are made to emit light to prevent toner adhesion (edge processing).

Further, the switch 29 provided near the document instruction table is turned on.
When the signal that detects the non-contact state between the document pressure plate 21 and the document table glass 19 is input to the input port ₁₂ of the MP55, the MP55 determines that the document 20 is a book.
Therefore, after the reflection density detector 35 detects the document edge, it is determined that the book is a set of book edges until a white reference higher than a predetermined reflectance is detected.
LED corresponding to this edge set in the eraser 41
A control signal is output to each of the output ports O _{1 to} O ₉ so as to emit light, and the drive driver 62 that receives the output drives the LED, and the LED corresponding to the edge aggregation portion emits light. This prevents toner from adhering to the gathering portion of the edges. When the document 20 is a book, a halftone having a reflectance lower than a predetermined reflectance is present in the center of the document in the reflection density detected by the reflection density detector 35, and as a result of the main operation, If a set of halftones exists in the edge direction of the document 20, the MP 55 determines that the halftones are due to the folds of the book, and the L corresponding to the position of the halftones in the eraser 41.
A control signal is output to each of the output ports O _{1 to} O ₉ so as to emit light from the ED, and the drive dryer 62 that receives this output drives and the LED corresponding to the halftone position emits light. This prevents toner from adhering to the halftone position.

Next, edge control in the document area will be described. Note that, hereinafter, the document pressure plate 21 is a mirror surface.

As described above, the reflection density of the original area is the reflection density detector 3
When the light receiving element group 71 of 5 detects each pixel,
After the set of pixels showing the temporary reflectance, the set of pixels showing the high reflectance (the original portion) is obtained. The document position and the document size are obtained from the boundary between the set of pixels having the low reflectance and the set of pixels having the high reflectance. In particular, when it is necessary to copy the original document 20 on the boundary, if the original document size and the original document position stored in the RAM 56 are copied, the original document 20 on the boundary, including the original document edge, will be toner-attached by the eraser 41. For this reason, it is determined from the reflectance of the pixel next to the pixel on the boundary whether or not the edge processing needs to be performed. That is, if a character or the like on the original is printed on the pixel next to the pixel on the boundary, the reflectance becomes low. If the reflectance becomes lower than the predetermined reflectance based on this determination criterion, the MP55 determines that it is necessary to attach the toner to the pixels on the document edge, and the predetermined magnification (for example, 98). %) To control copying so that it is reduced, and when the reflectance of the pixel next to the pixel on the boundary is higher than a predetermined reflectance, it is controlled to copy at the same size. Therefore, when there is a character or the like near the boundary, the character is reduced, so that the character near the boundary is not affected by the image erasing (edge processing) by the LED, that is, the eraser 41.

Next, the control operation of automatic scaling will be described.

As described above, the reflection density of the original area is the reflection density detector 3
When the light receiving element group 71 of 5 detects each pixel,
A set of pixels exhibiting high reflectance is followed by a set of pixels exhibiting low reflectance. The image area is obtained from the boundary between the set of pixels having the high reflectance and the set of pixels having the low reflectance. This image area and cassette size input key 57 ₁ ~
57 ₃ by comparing the copy sheet size of the copy paper housed in the upper cassette 12 or the lower cassette 13 is obtained, the copy at the same magnification if copying paper of the same size are accommodated in upper cassette 12 or lower cassette 13 I do.

On the other hand, if the image area and the copy paper size are different, the most appropriate reduction or enlargement is selected so that the entire image area is copied onto the copy paper, and copying is performed at a predetermined magnification.

Next, the automatic density control operation will be described with reference to FIGS. 1, 2 and 7.

FIG. 7 is a characteristic waveform diagram showing the density characteristics. The first quadrant shows the relationship between the exposure amount (E) and the electric potential (V) of the drum 1, and the second quadrant is the electric potential (V) of the drum 1 and is copied. The relationship with the image density (DC) is shown. The third quadrant is the copy image density (DC) and the reflection density detector 3.
5 shows the relationship with the document density (DO) obtained from the reflection density detected, and the fourth quadrant shows the relationship between the document density (DO) and the exposure amount (E).

As described above, the reflection density of the original area is the reflection density detector 3
When the light receiving element group 71 of 5 detects each pixel,
Pixels exhibiting low reflectance are obtained after the set of pixels exhibiting high reflectance. Of these, the one with the highest reflectance (ground color, standard white level) in the set of images showing low reflectance has a density of 0.
If the density is 07 and the density is 0.5, the input voltage of 65 V is applied to the irradiation lamp 25, and the first
The electric potential of the drum 1 is determined by the EV characteristic shown in the quadrant, and 1000 Hz of the developing characteristic shown in the second quadrant, 1
A copy image with a density determined by the 000 Vp-p curve can be obtained. In the above example, a document density of 0.07 is developed to a copy density of 0.07, and a document density of 0.5 is a copy density.
Developed to 0.5. That is, the original density and the copy density are the same.

On the other hand, when the difference between the maximum value and the minimum value of the document density is smaller than the predetermined value, the copy density is changed as follows.

For example, the original document density before change is 0.2 and the maximum value is 0.5.
If it is, it is assumed that the EV characteristic of the first quadrant does not change, and when the original density of 0.2 is changed to the copy density of 0.07, the input voltage of the irradiation lamp 25 shown in the fourth quadrant is set to 8
By controlling so as to set it to 0 V, the original density of 0.
Developed to 5. Also, the development characteristic of the second quadrant is 1600H.
z Control to set to 1800Vp-p. By this control, when the difference between the maximum value and the minimum value of the document density is smaller than a predetermined value, that is, the document 20 with unclear contrast is artificially added with the contrast to set an appropriate density. Obtain a clear copy image.

Next, the registration roller 14 and the eraser 4 with respect to the document position
The control of No. 1 will be described with reference to FIGS. 1 and 2.

The document table glass 19 has a predetermined document reference position, and when it is determined from the reflection density detected by the reflection density detector 35 as described above that the document leading end position deviates from this document reference position. Is the LED of the eraser 41 corresponding to the pixel of the light receiving element group 71 that has detected the low reflectance.
To prevent toner adhesion and delay the drive timing of the registration roller 14 to automatically align the registrations (copy paper leading edge and image leading edge) to correct the misalignment of the document leading edge from the document reference position and correct it. Images can be obtained. If it is found from the reflection density detected by the reflection density detector 35 as described above that the front end of the original is set to be inclined with respect to the reference position of the original more than the predetermined parallelism, Copying stopped and manuscript 2
A display requesting a reset of 0 is made.

Next, the control by the MP55 will be described with reference to the flowcharts of FIGS. 8 (a), 8 (b) and 8 (c). In addition,
(1) to (41) show each step.

When the power of the image processing device is turned on, the warm-up is started and it is judged whether or not it is the measurement position of the standard white board 22 (1),
The optical system drive motor 39 is reversely rotated until the position sensor 30 detects the position detecting piece 28 (2). If the standard white plate 22 is at the measurement position in step (1), the optical system drive motor 39 is turned off (3) and the irradiation lamp 25 is turned on (4).
Next, waiting for the input of the shift pulse signal SH, counting the A / Din signal at the time of the input of the shift pulse signal SH and performing a dummy process (5), then detecting the reflection density of the standard white board 22 and shifting again. The input of the pulse signal SH is awaited (6). After inputting the shift pulse signal SH, the irradiation lamp 25 is turned off (7) and the input of the copy start key is waited (8). After this, the process moves to the flow of FIG. 8 (b), and if there is a copy start input, it is judged whether the stop position of the moving optical system unit 24 is the position of the standard white board 22 (9), N
If it is O, the optical system drive motor 39 is rotated in the reverse direction (10). If YES in step (9), the optical system drive motor 39 is rotated forward (11), the moving optical system unit 24 is moved in the sub-scanning direction A, and the irradiation lamp 25 is turned on (12). Next, the position sensor 31 determines whether or not the moving optical system unit 24 has reached the copyable area (13), and if NO, waits until the copyable area is reached. If YES in step (13), set the initial values for the image area and original area.
(14) Further, the reference black level and the reference white level of the reflection density are set (15). After the setting, the shift pulse signal SH is waited for input and the A / Din signal is counted (16), and after the counting is finished, the reflection density of the image area in the sub-scanning direction A is detected and stored for each light receiving element of the light receiving element group 71. (17).

Then, it is judged whether the measurement of the reflection density of the copyable area is completed (18). If NO in the determination in step (18), the process returns to step (16) to continue detecting the reflection density of the copyable area. If YES, the dummy process similar to step (16) is performed and the irradiation lamp 25 is turned off (19).
Then, the reflection density stored in step (6) is corrected (2
0). Then, the reflection density corrected in step (20) and the reflection density of the reference black level set in step (15) are compared for each light receiving element (21) to obtain the maximum reflection density.
(22). Subsequently, similarly, the reflection density stored in step (17) is compared with the reflection density of the reference white level set in step (15) for each light receiving element (23), and the minimum reflection density is obtained and stored in the RAM 56. Yes (24). Figure 8 after this
Then, the procedure goes to the flow of (C), and then the reflectance is checked for each pixel of the reflection density data stored in step (17) (25) to form a set of pixels whose reflectance is less than 1, and the original size and The image area in the document size is detected (26), and the light emission of the LED of the eraser 41 corresponding to the non-document area is set (2
7). Next, it is checked whether the reflectance of the pixel next to the pixel on the contour of the document size detected in step (26) is higher than a predetermined reflectance (28), and if NO, the copy magnification is reduced. Set (29), set the LED emission of the eraser 41 according to this magnification (30), and then check if the cassette size is equal to the image size (3
1) If YES, the bias value of the developing device 7 or the light quantity of the illumination lamp 25 is set according to the reflection density stored in step (17) (34), and copying is started (35).

On the other hand, in the case of NO at step (31), the copy magnification is changed.
(32), the light emission of the LED of the eraser 41 is set according to the copy magnification (33), and the process proceeds to step (34).

On the other hand, if YES in step (28), the copy magnification is set to the same size (36). Then, it is checked whether or not the switch 29 is in the ON state (37), and if it is ON, the LED emission of the eraser 41 corresponding to the contour point of the document size is set (3
9), jump to step (31), and in the case of YES, it is determined whether or not there is a set of pixels showing low reflectance in the main scanning direction in the document size (38). If this judgment is YES,
The light emission of the eraser 41 corresponding to the low reflectance area in the main scanning direction in the document size is set (41), and the process jumps to step (31). If NO in step (38), the light emission of the eraser 41 corresponding to the pixels from the contour of the document size to the tip of the pixel area in the document size is set (40), and the process jumps to step (31).

〔The invention's effect〕

As described above, according to the present invention, when the discriminating means determines that the image area and the recording paper are different in size, the forming means is arranged so that the image in the image area is scaled to form a latent image. In addition to controlling, if the image area and the recording paper size are determined to match by the identifying means, but the image is determined to exist in the outline of the document area, the image in the image area is reduced to form a latent image. Since the forming unit is controlled as described above, there is an effect that an image can be recorded on the entire surface of the recording paper of the specified size without excess or deficiency of the document image and without erasing the image on the boundary between the document and the image.

[Brief description of drawings]

FIG. 1 is a sectional view of an image scaling apparatus showing an embodiment of the present invention, FIG. 2 is a control circuit diagram of the same, and FIG. 3 is a front view of a reflection density detecting element showing an embodiment of the present invention. FIG. 4 is a density characteristic waveform diagram showing the relationship between reflection density and output voltage, FIG. 5 is a scanning scan schematic diagram showing division in the scanning direction, FIG. 6 is a timing chart of each control signal, and FIG. The characteristic waveform diagram shown in FIGS. 8A, 8B, and 8C is a flowchart showing an example of control. In the figure, 1 is a drum, 2 is a precharger, 3 is a primary charger, 4 is a charger, 5 is a copying charger, 6 is a cleaning device, 7 is a developing device, 8 is a pre-exposure lamp, and 9 is the entire surface. Exposure lamps 10, 11 are paper feed rollers, 12 is an upper cassette, 1
3 is a lower cassette, 14 is a registration roller, 15 is a conveyor belt, 16 is a fixing roller, 17 is a discharge roller, 18 is a tray, 19 is a platen glass, 20 is a document, 21 is a document pressure plate, and 22 and 23 are standard white plates. , 24 is a moving optical system unit, 25 is an irradiation lamp, 26 is a first scanning unit, 27 is a second scanning mirror, 28 is a position detecting piece, 29 is a switch, 3
Reference numerals 0, 31, and 32 are position sensors, 34 is a document detection lens, 36 is a projection lens, 35 is a reflection density detector, 37 is a third scanning mirror, 38 is a fourth scanning mirror, 39 is an optical system drive motor, and 40. Is a main motor, 41 is an eraser, 5
1 is an oscillator, 52 is a frequency divider, 53 and 60 are amplifiers, 54
Is an A / D converter, 55 is a microprocessor, and 56 is R
AM, 57L1~57 ₃ cassette size input key, 5
8 is an input key, 59 is a D / A converter, 61 is a lamp regulator, 62 and 63 are drive drivers, 64 ₁ and 64 ₂
AND circuits 65 ₁ inverter, 65 ₂ AND circuit, 66 denotes an inverter, the clock signal 67, 71 is a light receiving element group.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Naoyuki Oki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Masanori Miyata 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (56) Reference JP 59-72856 (JP, A) JP 56-141665 (JP, A) JP 57-141636 (JP, A) JP 61-6672 (JP, A) A) JP-A-61-6640 (JP, A)

Claims (1)

[Claims] 1. A document table on which a document is placed, scanning means for scanning the document table on which the document is placed, and a latent image corresponding to an image recorded on the document placed on the document table. Forming means for forming an image on a charged photoreceptor, eraser means for removing unnecessary charges on the photoreceptor, transfer means for transferring the latent image formed on the photoreceptor onto a recording sheet, Detection means for detecting the density of the document table surface on which the document is placed based on the scanning by the scanning means, and a document area placed on the document table and an image recorded on the document based on the detection result of the detection means. When the area identifying means identifies the area and the identifying area determines that the size of the image area and the size of the recording paper are different, the image of the image area is magnified according to the ratio of the size of the image area to the size of the recording paper. So that a latent image is formed by scaling When controlling the forming means and determining that the image area and the recording paper size match by the identifying means, it is determined that the image does not exist in the contour portion of the original area, the image of the image area is determined. And a control unit that controls the forming unit so that the image in the image area is reduced by a predetermined magnification to form a latent image when it is determined that the image exists in the contour portion of the document area. An image scaling device characterized by comprising: